1. Field of the Invention
The present invention relates to a tangential airstream heat shrinking device of plastic film, and in particular to a device that is applicable to heat shrinking package and comprises a high-temperature airstream ejector that has a plurality of circumference tangential heat-shrinking routes of different angles for uniformly heating an external plastic film of the package.
2. The Related Arts
In a heat shrinking packaging process using a heat shrinking film, except a heat shrinking film wrapping operation, a primary packaging mechanism is the heating device for heat shrinking. The conventional heating device for heat shrinking is generally set up at one side, or both sides, or a top side of a packaged article. Thus, in heating the heat shrinking film wrapped externally around the packaged article, the routes along which high-temperature airstreams are ejected are only set at one side, both sides, or the top side of the packaged article. The manner of heating that is conventionally adopted is generally heating through high temperature airstream moving along linear routes. This generally results in inhomogeneous shrinking of the heat shrinking film wrapped externally around a packaged article. The outside appearance of the heat shrinking film package around the packaged article may be deformed or even broken. This deteriorates the quality of heat shrinking packaging and is thus a major issue to be addressed by the heat shrinking packaging device.
Related prior art references are known, such as Taiwan Utility Model M348070, which discloses a high-temperature airstream heating device, Chinese Patent Application No. 201010543690.7 (Publication No. CN102050243), which discloses a shrinking tunnel, Chinese Patent Application No. 200780052373 vehicle safeguard device 1 (Publication No. CN101641260), which discloses a shrinking oven that shrinks a shrinkable film over a packaged article or a packaged unit, and Chinese Patent Application No. 01818418 mold frame 9 (Publication No. CN1473125), which discloses a heat shrinking tunnel of packaging machine featuring high adaptability. All these references disclose conventional heating devices for heat shrinking, wherein high-temperature airstream heating devices are set up at two sides of a packaged article. Although heating can be conducted for packaged articles of different sizes, yet the manner of heating the heat shrinking film wrapped externally around the packaged article is still conducted in high-temperature airstream direct heating through linear routes and thus may still cause inhomogeneous heat shrinking of plastic film, eventually leading to problems and shortcomings, such as deformation of outside appearance formed after heat shrinking of the heat shrinking film, breaking, and being not able to improve quality of the packaged article.